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Lemoynite mineral

Hydrated sodium-calcium-zirconium phyllo/tectosilicate mineral of the lemoynite group with current September 2026 IMA-CNMNC approved formula Na2CaZr2Si10O26(H2O)5-6, status A, and approval number IMA 1968-013. Perrault, Semenov, Bikova, and Capitonova (1969) originally described lemoynite from pegmatites of the Mont Saint-Hilaire alkaline intrusion, Rouville County, Quebec, Canada, reporting a classical wet-chemical analysis (Table 2, p. 591: SiO2 47.32, ZrO2 23.23, TiO2 0.43, Nb2O5 2.18, RE2O3 1.18, Fe2O3 1.62, MnO 0.10, CaO 5.06, SrO 0.05, Na2O 4.75, H2O 13.33, total 99.25 wt%) and monoclinic symmetry (a = 10.48, b = 16.20, c = 9.07 A, beta = 105 degrees 20 minutes). Le Page and Perrault (1976) re-analyzed Mont Saint-Hilaire lemoynite by XRF and atomic absorption (Table 1, p. 133: SiO2 55.40, Al2O3 0.22, ZrO2 20.30, Nb2O5 0.87, TiO2 0.49, CaO 4.40, MnO 0.04, Fe2O3 0.57, TR2O3 <1, ZnO 0.19, CuO 0.08, SrO 0.07, MgO 0.16, K2O 3.70, Na2O 3.02, Rb2O 0.03, H2O 9.50, total 99.04 wt%, showing that the 1969 analysis had underestimated SiO2 and missed K2O) and solved the crystal structure in monoclinic space group C2/c with doubled c axis (a = 10.384(3), b = 15.947(7), c = 18.601(6) A, beta = 104.59(3) degrees, Z = 4, R = 7.9% for 4200 intensities; C2/m pseudocell with c' = c/2 = 9.300 A), revealing a rigid open [ZrSi5O13]2- framework of 7-A-thick hexagonal-ring silicate sheets linked by 6-coordinated [ZrO6] octahedra and pervaded by wide tunnels containing disordered Na+, K+, Ca2+, and H2O molecules. Distinct from natrolemoynite, armstrongite, elpidite, and elemental zirconium; no criticality designation, microbial mechanism, or industrial recovery yield is asserted.

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Identifiers & Classification

System Identifier Label
IMA IMA:1968-013 Lemoynite

Microbial & Biochemical Mechanisms (1)

Lemoynite other Laboratory thermal channel dehydration

Laboratory thermal channel dehydration of natural lemoynite with framework retention

other

Heating natural Mont Saint-Hilaire lemoynite up to 200 degrees C (with DTA endotherm at 140 degrees C and main TGA mass-loss step at 135-200 degrees C, and isothermal dehydration at 200 degrees C for 24 hours) expelled the loosely bound tunnel H2O molecules—eliminating the infrared H-O-H bending absorption bands at 1615/1618 and 1668 cm-1 and O-H stretching bands at 3400 and 3600 cm-1—while leaving the Si-O infrared bands (800-1200 and 400-550 cm-1) and the Debye-Scherrer X-ray powder diffraction pattern of the rigid [ZrSi5O13]2- framework completely unchanged.

Experimental Context & Analytical Limits:
Thermal and spectroscopic experiments in Perrault et al. (1969), pp. 589-593 and Figures 2-3, combined thermogravimetry (recording ~8 wt% rapid loss around 135 degrees C and ~13.3 wt% total loss up to 900 degrees C), DTA (endothermic peak at 140 degrees C), infrared spectrophotometry (400-3800 cm-1 in CCl4 and mineral oil mulls on unheated lemoynite versus lemoynite heated at 200 degrees C for 24 hours), and Debye-Scherrer X-ray powder photography before and after 24-hour heating at 200 degrees C.
Curated Evidence Points:
Pages 589-593 and Figures 2-3 demonstrate that heating lemoynite at 200 degrees C for 24 hours removes the H2O infrared absorption bands at 1615/1618, 1668, 3400, and 3600 cm-1 while yielding an X-ray powder diffraction film identical to unheated lemoynite.
Pages 135-138 confirm structurally that the [ZrSi5O13]2- framework forms open 7-A-wide channels housing disordered zeolitic H2O and exchangeable cations, accounting for the topotactic dehydration without framework collapse.

Sources & References

  1. ima_2026_09: IMA-CNMNC, The New IMA List of Minerals, September 2026, PDF page 123, Lemoynite row: formula Na2CaZr2Si10O26(H2O)5-6, status A, IMA No. 1968-013, country Canada, first reference Canadian Mineralogist 9 (1969), 585, second reference Canadian Mineralogist 14 (1976), 132; column definitions on PDF page 1.
    https://cnmnc.units.it/files/editor/IMA_Master_List_(2026-09).pdf (accessed 2026-10-22)
  2. perrault_1969_lemoynite: Perrault G, Semenov EI, Bikova AV, Capitonova TA (1969), La lemoynite, un nouveau silicate hydrate de zirconium et de sodium de St. Hilaire, Quebec, Canadian Mineralogist 9:585-596. Complete 12-page primary PDF visually inspected: Mont Saint-Hilaire occurrence, X-ray crystallography Table 1, wet chemistry Table 2, DTA/TGA thermal dehydration Figure 2, infrared spectra before and after 200 C dehydration Figure 3, and powder XRD Table 3 pp. 585-596.
    https://www.rruff.net/doclib/cm/vol9/CM9_585.pdf (accessed 2026-10-22)
  3. le_page_1976_lemoynite: Le Page Y, Perrault G (1976), Structure cristalline de la lemoynite, (Na,K)2CaZr2Si10O26, 5-6H2O, Canadian Mineralogist 14:132-138. Complete 7-page primary PDF visually inspected: revised XRF/AAS chemical analysis Table 1 and monoclinic C2/c crystal-structure refinement Tables 2-6 and Figures 1-2 pp. 132-138.
    https://www.rruff.net/doclib/cm/vol14/CM14_132.pdf (accessed 2026-10-22)

Curation History

Timestamp Curator Action Summary
2026-10-22T07:20:00Z antigravity CREATE Created lemoynite mineral record with verified IMA:1968-013 identity, 1969 original description and thermal channel-dehydration mechanism, and 1976 monoclinic C2/c crystal-structure refinement.

Record source: data/records/lemoynite.yaml